Tommy Tobin

Recent studies have shown that listeners can achieve accurate pitch perception at high frequencies (> 8 kHz) as measured by fundamental frequency (F0) discrimination. However, it is unknown whether listeners can perform more complex pitch perception tasks at high frequencies, such as identifying melodies or the quality of a chord. In this project, we addressed this question by measuring the ability of listeners to (1) identify whether two four-note melodies were the same or different and (2) identify whether a triad was major or minor. In both experiments, the stimuli were composed of complex tones that were bandpass filtered either from ~1500-3000 Hz in the low-frequency condition or from ~8000-15000 Hz in the high-frequency condition. In the melody experiment, listeners were sometimes exposed to a concurrent tonal masker that interfered with their ability to do the task. In the triad experiment, listeners heard chords in which each note was played concurrently as well as chords in which the notes were presented in a repeating sequence (i.e., the notes did not overlap in time). Preliminary results revealed that listeners could perform the melody task at both low and high frequencies, although the tonal masker impaired performance in both cases. In contrast, listeners could only perform the concurrent triad task at low frequencies, but some listeners demonstrated the ability to perform the sequential triad task at both low and high frequencies. These results will provide insight into how the pitches of multiple concurrent sounds are processed in the human auditory system.